A portable way to calculate pointer to the whole structure using pointer to a field declared inside the structure (aka CONTAINING_RECORD macro)

Question

There is the well known CONTAINING_RECORD() macro defined, for instance, in Winnt.h:

#define CONTAINING_RECORD(address, type, field) ((type *)( \\
                  


        

Answer 1

Your ways to determine the address of the containing structure work only if 'type' is a type that does not use multiple inherritance. Otherwise, the macros would dereference the NULL pointer, and that is always guaranteed trouble. I once asked a question about this matter ( Is this valid ANSI C++ code? Trying to generate offsets of structure members at compile-time ).